This invention relates to steerable shafts, and more particularly to a hollow cannula tip which may be remotely steered (or deflected) by a user. Although preferred embodiments lie in the medical field, wherein the cannula may carry an endoscope or surgical tool, other uses are possible.
A variety of deflecting tip cannulae have been used or proposed for endoscopic or endosurgical use. In some such systems, such as that shown in U.S. Pat. No. 5,656,011 issued to Uihlein et al., the cannula is formed of a series of stacked, interlocking annular vertebrae. The vertebrae may be articulated via pulling on a tension spring band to flex the cannula from an initial, typically straight, configuration. Alternatively, with a preflexed cannula, a stiff sleeve may be extended and retracted over the cannula so that only the portion of the cannula distally beyond the sleeve is flexed.
U.S. Pat. No. 4,580,551 issued to Siegmund et al., discloses a cannula with a series of transverse slots or notches which serve to enhance flexibility of the cannula within a preferred bending plane. Articulation may be achieved via the use of four pull wires evenly disposed about the periphery of the cannula.
U.S. Pat. No. 5,307,803 issued to Matsuura et al., discloses an endoscope having a finned flexible member jacketed by a thin flexible tube. Channels defined by the fins contain one or more optical fibers and pull wires.
The invention provides a steerable probe with a deflectable tip. In one embodiment, the probe may include a cannula having a proximal end and a distal end and extending along a length therebetween, an exterior surface, an interior surface defining a lumen, an elongate flexible section extending along a first portion of the length and having a section proximal end and a section distal end. A pull wire for deflecting the flexible section in a first direction in a preferred bending plane may be substantially embedded in the cannula between the interior surface and the exterior surface and extending from the section proximal end to the section distal end. The pull wire may be secured to the cannula adjacent to the section distal end, freely passing through the section proximal end. Two longitudinal strengthening members may be embedded in and extend along the flexible section generally opposite each other about the preferred bending plane. The invention also includes method of manufacturing such a structure.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.